The inventor has examined how to precisely recognize the position of a carriage in a curve section. Successful precise recognition, for example, enables the recognition of the position of the carriage in all the sections of a running route from a start point to a destination. As a result, the carriage can reach the destination in an intended running time without unwanted acceleration or deceleration. A reduction in the need for acceleration or deceleration enables the minimization of vibration to which articles may be subjected during conveyance.
The inventor has further examined how to precisely recognize the position of the carriage in a curve section to enable the carriage to be stopped at a predetermined position even in the curve section, thus allowing a station to be provided in the curve section. If this is successful, restrictions on the installation of stations can be reduced to allow a carriage system to be flexibly laid out.
In connection with the recognition of the position of a guided carriage in a curve section, the Unexamined Japanese Patent Application Publication (Tokkai-Hei) No. 8-292813 discloses a technique for correcting an output from an encoder for the curve section so as to vary a determined running distance between a curve section and a rectilinear section even if the output is the same for both sections. However, such positional recognition is an approximate technique and is not suitable for the recognition of the exact position in the curve section.